1. Field of the Invention
The present invention generally relates to a package structure for use in an integrated passive device (IPD) and a method for forming a package structure. In particular, the present invention is directed to a package structure with a conductive element substantially consisting of a passive element and of a corresponding circuit on a non-conductive substrate and a method for forming the package structure.
2. Description of the Prior Art
The purpose of an integrated passive device (IPD) resides in combining multiple passive elements on a substrate to provide an integrated device module of a specific function. FIGS. 1 to 4 illustrate a current method for forming a package structure including electronic elements. Please refer to FIG. 1, which discloses a multilayer structure 101 with composite material layers. Such multilayer structure 101 with composite material layers includes a conductive substrate 110, a corresponding circuit 121, an electronic element 122, a resin material 130 and a transparent layer 140. The conductive substrate 110 which is illustrated here is a semi-conductive substrate such as Si. The electronic element 122 may be a photosensor, and the electronic element 122 and the corresponding circuit 121 are electrically connected to each other and together disposed on the conductive substrate 110. The resin material 130 covers the corresponding circuit 121 and the electronic element 122. The resin material 130 may be an epoxy resin. There is an additional transparent layer 140, such as glass, on the resin material 130 to allow the photosensor to pick up optical signals.
Second, as shown in FIG. 2, first the conductive substrate 110 is polished to reduce its thickness, then an etching step is carried out to define the scrub lines 150 on the conductive substrate 110. Later, as shown in FIG. 3, a combining material (not shown) is applied to combine the structure 101 which now has the defined scrub lines 150 with a carrier 160 of a glass-type material to be later mechanically processed to form a notch 151 which corresponds to the scrub lines 150, in order to expose the corresponding circuit 121 which is electrically connected to the electronic element 122. Next, the patterned conductive layer 123 which covers the carrier 160 and the conductive substrate 110 as well as a corresponding solder 124 which is disposed on the conductive layer 123 are formed. The conductive layer 123 makes the corresponding solder 124 indirectly electrically connected to the corresponding circuit 121 because of covering the notch 151 and being electrically connected to the corresponding circuit 121.
Afterwards, please refer to FIG. 4, solder balls 125 are formed on the solder 124 to serve as the outward electrical conductive media of the corresponding circuit 121 in the multilayer structure 101. After the completion, the entire multilayer structure 101 can be processed and diced mechanically through the scrub lines 150 to get multiple electronic products in single piece.